R' Yehoshua and R' Nechunya ben Elinasan, the leader of Kfar HaBavli, testified concerning a limb of a corpse, that it is tamei. For R' Eliezer says: They did not say [this] except regard-ing a limb from a living [person]. They said to [R' Eliezer]: Is it not a kal vachomer? If even [regard-ing] a living [person], who is [inherently] tahor, a limb that becomes detached from him is tamei, [then regarding] a corpse, which is [inherently] tamei, is it not logical that a limb that becomes detached from it should be tamei? [R' Eliezer] said to them: They did not say that a limb transmits tumah except regarding a limb that was severed from a living person. Alternatively, the tumah [emanating] from the living is [in a sense] greater than the tumah [emanating] from the dead. For a living [zav] renders tamei a couch or a seat [that is] underneath him to contaminate a person [who touches the couch or seat] and to contaminate [his] clothes; and [the zav also renders tamei] that which is above him [and rests on him with] a light tumah, to contaminate foods and beverages [only]; where-as a corpse does not contaminate [in this manner].